The present invention, in some embodiments thereof, relates to methods and/or apparatus for detecting and/or treating gait disorders, in particular episodic gait disorders, more particularly, but not exclusively, freezing of gait disorders, whether associated with Parkinson's disease or not.
Freezing of gait (FOG) is a paroxysmal gait disturbance, a sudden, transient and unpredictable interruption of walking. FOG typically manifests as a sudden and transient inability to move. The patient attempts to move forward, inexplicably however, he/she is unable to. Patients report that their feet are “glued to the ground”. FOG is a debilitating phenomenon that significantly reduces functional independence and often leads to wheelchair use.
The population which suffers mostly from FOG are subjects with Parkinson's disease (PD). FOG is common in subjects with advanced Parkinson's disease (PD), however one should bear in mind that FOG is a symptom complex that occurs in several disorders which also often involve cognitive impairment, e.g., progressive supranuclear palsy, multiple system atrophy, corticobasal degeneration, dementia with Lewy Bodies and higher level gait disorders. Manifestation of FOG is variable within and across subjects, yet a few subtypes have been described. These include, for example, freezing that occurs at the start of walking (i.e., gait initiation), during turns, when passing tight quarters and also during simple walking in an open runway. FOG has a grave impact on quality of life as it is largely associated with falls, interferes with daily living functions, and causes reduced activity and self-imposed social isolation.
The pathophysiology behind the symptom is not clear. A number of theories have been proposed mainly in reference to patients with PD. Briefly, the breakup of regular gait that results in a subject who is virtually ‘frozen’ in one place lacking the ability to produce effective progression, is hypothesized to stem from deterioration of certain gait features, (or inability to start the operation of these gait features in case FOG occurs at the start of walking) to an extent that gait cannot be regulated. Gait features that were implicated with FOG are gait rhythmicity, left-right stepping coordination, step length scaling, gait symmetry and dynamic control of postural stability. Each of these gait features is compromised even during the functional periods of locomotion preformed by PD patients that suffer from FOG (PD+FOG), and their background impaired condition is related to the pathological condition of the brain in PD. For example, bilateral coordination of gait is impaired in PD, possibly due to the un-even neuronal loss seen on both sides of the brain in this neurodegenerative disease. Major dopaninergic depletion in the Basal Ganglia, a brain region that normally facilitates movement scaling, is most likely behind the step scaling problem in this disease. It was also hypothesized that additional pathological conditions overlap with these gait impairments to distinguish those PD patients who will suffer from freezing from those who will not. For example, reduced cognitive capacities, in particular in the executive function domains, were associated with and believed to contribute to freezing in PD.
Methods for diagnosing and treating FOG are quite limited. Often patients who report many freezing incidents during their daily routine fail to exhibit even one under examination at the neurologist's office, most likely due to psychological effects. Therefore the effectiveness of proposed treatments is evaluated only in a limited manner. Even among patients who do present with FOG in the clinic, it is difficult to quantify the magnitude of the problem. This limits the ability to evaluate the effectiveness of any treatments attempts.
Subjective assessment is currently used to determine the severity of freezing. Several questionnaires are in common use in clinical practice that assess if freezing occurs, how often and under which circumstances. These quaternaries sometimes obscure the correct clinical pictures since sometimes patients change their reports between consecutive visits that are separated by only a short period of time. Actually, this problem led to the creation of a questionnaire in which spouses and caregivers both provide information. Recently, mobility sensors were suggested alternative for the assessment of the FOG burden. Current treatments are based on pharmacological treatments. Recently some have suggested using surgical implantation of stimulating electrodes to specific parts of the brain, however, this is not widely accepted, is quite invasive, and the evidence for its efficacy is not yet strong.
FOG is generally not well addressed by current treatment approaches. Immediate, small, short-term improvements in FOG have been demonstrated in a handful of studies. Many of these focus on the use of visual or auditory cues to facilitate movement and reduce FOG. There is evidence that PD+FOG may respond differently to cues than PD-FOG and that appropriate cues can, while present, result in improved velocity and stride length and reduced FOG. A large randomized trial examining the effects of cueing on FOG demonstrated slight improvements in FOG (5.5% reduction) but little retention of benefit six weeks after training. The effects of a comprehensive physical therapy program that included cueing on FOG, demonstrating improvements in FOG immediately following a 6-week intervention but a return to baseline levels of FOG one month later. Preliminary work on turning, e.g., when the subject turns left, right or in a circle, suggests that rotating treadmill training may have a dramatic effect on FOG when the subjects walk in normal daily conditions after the intervention.
To date, methods for diagnosing and treating FOG are quite limited. Often patients who report many freezing episodes during their daily routine fail to exhibit them under testing or examination conditions such as at the neurologist office. Therefore the effectiveness of prescribed treatments is evaluated only in a limited manner. Even among patients who do present with FOG in the clinic, it is difficult to quantify the magnitude of the problem as it is episodic. In addition, due, in part, to the variable nature of the appearance of the symptom, standardized treatment approaches are not effective.